Self-generating gas flow interrupter

Abstract

An electrical circuit interrupter is disclosed having the characteristic of a puffer interrupter and a self-extinguishing gas flow interrupter. The interrupter comprises a generally hollow movable cylinder which is adapted to be filled with an arc extinguishing fluid and which has an opening at one end. A piston is sealingly and coaxially disposed within the cylinder so as to be movable between a first and second position to change the internal volume of the cylinder in flow communication with its opening. A fixed guide is provided to direct the motion of the piston within the cylinder. A stop is carried by the guide to limit the relative motion between the piston and the cylinder. A spring biases the piston against the stop. Disposed at the open end of the cylinder is an arc site such that the pressure within the cylinder increases as the energy released from the arc increases. One of the two contacts across which the arc is formed is carried by the cylinder. Thus, under low or no arc conditions, the piston is held by the biasing means against the stop as the cylinder moves relative to it. This forces arc extinguishing fluid in the vicinity of the arc. Under high current carrying or fault conditions, the biasing means is overcome by the energy released from the arc to control the temperature and pressure rise adequately enough to extinguish the arc by the self extinguishing principle.